You understand it perfectly! You just don't want to accept it, which is completely fair. The problem you face is that if you don't want to accept what the powerful are doing you have to oppose them, and you and I both know how hard that is, and how the prospect of success is fairly low (revolutions do succeed, but they are not common).
Britain and the British and the British King (from a few centuries ago) have plenty to do with Canada. The concept is "honour of the Crown", meaning if the Crown did something in 1763 that we find kind of stupid today we still have to abide by it because of...the honour of the Crown. Again, you understand that, but may not want to accept it (and there is a reasonable argument for rejecting it, but boy oh boy you'd be facing an uphill climb).
Then, of course, there's the whole common law president thing.
Bottom line: Indigenous title is a real thing that's been recognized by Canadian courts. We can keep pretending that the recoginition of Indigenous title isn't a real thing, but it's not a strategy that's going to work unless you've got people ready to take up arms and oppose the current government structure in this country. I can't see that happening.
Do you have another way to get around Indigenous title?